Flashbulbs
Flashbulbs provide light for photography where there is insufficient "available" light. Origins Before flash bulbs, flash photography relied on openly burning powder - usually containing magnesium. In 1893, Chauffour made an ancestor of the flash bulb; this had magnesium ribbon in a glass bulb, and was fired electrically- but this had been designed for underwater photography. The first recognisable flash bulb for general use was invented in 1925 by Vierkötter - using flash powder in an evacuated light bulb, fired by a lamp filament. Later that year, Vierkötter made a low-pressure oxygen-filled bulb. There are conflicting reports of the first commercial bulbs - made either by General Electric in the US, c.1927, or the Vacublitz alumimium foil bulbs made by Ostermeier in Germany, c.1929. The first wire-filled bulbs are reported to have been made by Philips in the Netherlands, in 1934.Focal Encyclopedia of Photography, revised ed. 1969, Focal Press, London Individual Bulbs Initially, flash bulbs were individual, disposable items - used once, then discarded. These are fitted into a flash gun, which may be a built-in to the camera, or an added-on accessory. Bulbs improved on earlier flash systems by safely enclosing the material which could otherwise throw burning embers over the subject and emit large quantities of smoke. Bulbs contained various materials, often magnesium or zirconium wire or foil. Early bulbs were very like domestic light-bulbs, including a metal cap with a screw (ES/Edison Screw) or bayonet (BC/Bayonet Cap) fitting. Costs were lowered by making bulbs with wire contacts emerging from the glass, and omitting the cap. Later bulb designs incorporated plastic coatings, to try to prevent bulb bursts - or at least contain the broken glass. These coatings were usually coloured blue - to give a colour temperature closer to daylight for use with colour film. One particular cause of bursting is cracking and subsequent leakage of air into the low-pressure oxygen of the bulb; to reduce the chance of this, most bulbs had a blue indicator spot on the inside, which would change colour in air. Use of this blue spot was continued in flashcubes & magicubes. http://farm3.static.flickr.com/2127/2373995173_9d9e10fc33.jpg http://farm1.static.flickr.com/181/400035441_b8f5e6a64d_m.jpg http://farm3.static.flickr.com/2297/2402990456_9171e7f50b_m.jpg An AG3B bulb, about 1 inch (2.5cm) long showing blue coating & blue air-leak indicator spot An older, larger General Electric bulb, in a flashgun on a Minolta 16 II Bulb flashguns could dwarf even large cameras Virtually all disposable flash bulbs and systems have now been replaced by re-usable electronic flashguns. A very few photographers still use bulbs for special effects, or the sheer power that bulbs can produce; see, for example the flashbulbs.com link (below) for current usages and supplies. Synchronisation Flashes need to be synchronised to the opening of the shutter. On early systems, this was done simply by opening the shutter (or removing the lens cap) and firing the flash by hand. Electrical operation allowed automatic synchronisation to the shutter. Firing early bulbs electrically required a specialised battery of around 15-25v in the flashgun or camera, although some large bulbs were designed for 110 or 240volt mains ignition1. There are variations in synch requirements - see Flash sync for more details. Multiple Systems These consist of a number of bulbs packaged together, with an automatic method of firing the next unused bulb. These were common on cheap, snapshot type cameras such as Instamatics and Polaroids. Individual disposable flash bulbs had several disadvantages: * Bulbs could be fiddly and slow to insert into a flashgun; the wire contacts could be bent and fail to connect, and the glass could break in the fingers. The gun itself may need to be opened and closed in addition. * Once fired, the bulb needed to be ejected; at this point it was hot enough to have blistered the glass and burn anything it landed on, and could sometimes have shattered into small sharp shards as it fired. Often a guard had to be removed from the gun before the bulb could be. * Taking another picture required the whole process to be repeated. Various systems avoided these problems by enclosing multiple bulbs into a package - with some mechanism for automatically firing the next unused bulb. This keeps the glass and contacts away from fingers and allows rapid changes. There were three major systems: Flashcubes, Magicubes and Flipflash. Flashcubes Flashcubes, introduced in the early 1960s, had four AG1-sized bulbs, on four sides of a cube, with a plastic reflector behind. The camera had a socket to insert the cube, which would rotate as the film was wound to bring the next bulb to the front. Cubes were fired electrically by lower-voltage batteries than most individual bulbs - use of two AA batteries was common. Magicubes Magicubes (X-Flashcubes) were an improvement on flashcubes, introduced in 1970. They looked almost identical to flashcubes, but were fired mechanically by a pin sticking into a capsule of fulminating material. This simplified the system compared to flashcubes - by removing the need for a battery, and made extremely cheap flash cameras possible. Magicube sockets were similar to flashcube ones, but were distinguished by being marked with an X - similarly the cubes themselves usually had a large X on the top. Flipflash Flipflash featured an array of 8 or 10 bulbs in a flat rectangular arrangement, each bulb placed horizontally, one above the other. Fuses selected the next bulb to fire; when half the bulbs were used, the photographer had to invert the Flipflash - which had a connector on both ends - to use the remainder (hence the name). The camera had a small rectangular socket to mount the Flipflash. Flipflash was subject to several patents; to get around these, and to fit their own cameras, other manufacturers arranged theirs differently, and some had other names for the system: Philips Topflash Topflash was very similar to Flipflash, but placed the bulbs vertically, two per row in an 2×4 arrangement. Polaroid Flash Bar Another Flipflash variation. Flash Bar bulbs were placed vertically, and arranged next to each other horizontally. Both sides had bulbs, the bar being rotated to use the other side. Sylvania Flip Flash Flip Flash bulbs were arranged in a zig-zag manner. Sylvania also made a Polaroid bar arrangement. Links * Flash (including photos of Instamatic adaptors) on Mischa Koning's Kodak Classics site * Magicube & Flashcube Photos + Tech Data on Flashbulbs.com - a current flashbulb supplier! Data on other bulbs here too. * Photos of Flipflash Assembly on protom.org * Photos of Magicube Assembly on protom.org Category:flash